My 1992 K75 Will Not Start

[gag1025]

It ran fine a week ago. The engine turns over but it will not crank. It is sitting on the center stand in neutral. I checked the pump and it works fine. I detached  the fuel line at the fuel supply pipe (rail) and it pumps fuel out in a steady stream. I checked the plugs and each plug is wet. That says to me that the injectors are OK. Each plug has a good spark. I even drained out all the fuel and replaced it with newly purchased fuel. It still will nit crank. This is the first bike I have ever had that is computer controlled. Any thoughts before I take it to my local BMW dealer?

[rbm]

I'm sorry.  I'm confused.  You say the engine will turn over but won't crank.  These are synonymous terms; they mean the same thing.  So what is exactly happening?  Are you saying that the starter motor turns the engine over but the engine will not fire?  Have you gone through all the suggestions in the stickies about this topic?

[gag1025]

Yes it turns over (cranks) but will not start. Plugs are wet and the plugs have fire. I threw out the gas in the tank and put 2 gal. of new fuel.

[gag1025]

On my other non computer bike when you have fuel at the plugs and fire at the plugs it will run.  Apparently in fuel injected bikes this is not true.

[rbm]

Follow Bert's troubleshooting chart at http://k-bike-knowledge.000webhostapp.com/electrical/EFI/bike-wont-start-EN.htm to isolate the potential problem.  It could be as simple as a connector has come loose, like on the ECU.

[gag1025]

Thanks for the information RBM. I will let you know what I find out.

[The Mighty Gryphon]

I recently had the engine flood on my K100RS with Motronic.  It is important in cold weather to not have any throttle when starting.  One problem I have noticed is that once the engine is flooded it will continue to flood if it doesn't start to run.

I have found that the easiest way to start a flooded brick engine is to disconnect the tank electrical plug and then crank the engine for 10 seconds with the throttle wide open.  This should blow enough gas out of the cylinders so that when you reconnect the tank and fuel pump the engine should start.

Regarding spark, how old are your plugs?  It is a lot harder for plugs to spark into the higher pressure in the cylinder at the top of the compression stroke.  If your plugs have more than a couple years or 20,000 miles on them you might want to spring for a new set.

Besides plugs, old wires and in some cases coils may be to blame.  Almost any weak component in the ignition circuit could result in a weak spark.

Another source of trouble this time of year is water in the gas.  Water collects in the low points of the tank and depending on how you do it and how much gas you remove you may have left most of it in the tank to mix with the new gas.  Even if you got it all out of the tank, there still may be some residual in the rail and the injectors that may take a bit of cranking to completely flush through the system.

[alexg]

Is it there a way to check the timing in these bikes ?
I had a BMW e36 that used to flood. Get the plugs out, cook them a little in your gas stove or use a gas torch, blow hot air all over the head to evaporate any remaining wetness, install the dry plugs and before everything cools down, crank it with a freshly charged battery.
One more: BMW cars used to have a feature that cuts the fuel supply when accelerator was fully depressed, just for the purpose of starting a flooded engine. Is there such a feature in our bikes?


Sent from my iPhone using Tapatalk

[Laitch]

Is it there a way to check the timing in these bikes ?

BMW cars used to have a feature that cuts the fuel supply when accelerator was fully depressed, just for the purpose of starting a flooded engine. Is there such a feature in our bikes?

Don't go off the deep end, alexg. :giggles Gryph already explained how he clears a flooded K-bike engine. Why doesn't gag try that first instead of mixing eclairs with profiteroles?

[gag1025]

The Mighty Gryphon. The plugs are new. I drained all the gas out and put 2 gallons of new gas in. Thanks for the information. I also saw a You Tube video that said that when this type of situation happens to squirt 10 cc of oil in each plug to seat the pistons. Is this true?

[gag1025]

[font=]The Mighty Gryphon, One other point. The fire at each plug is very strong.[/font]

[The Mighty Gryphon]

Okay, it sounds like you might have flooded it.  Just pull the plug to the tank and crank for 10 seconds with full throttle.  Then plug it back in and try to start but don't touch the throttle other than putting the "choke" to the first position.

The oil trick is a Chris Harris thing.  He says it's only necessary for an engine that has been sitting for 3-4 months to help seal the rings to get a bit more compression.  I doubt you need to do that since the bike was running just a couple weeks ago.

[thomas.weisman]

Hello im lookinh for advice i have 92 chevy 3500 dually with 2 barrel 454. Im having half throttle issiez boggs out half throt of full board before issue i had a return line blow off on tranny oil everyweear fixed issue then coyple weeks later started to have these half tgrottle issues after it had backfired early in morning ive replacr alot of sensors rinning out of options


Sent from my LG-LS777 using Tapatalk

[The Mighty Gryphon]

You needs to do an Italian tuneup.

Three or four bottles of Techron in the tank and go get some yeehaaaa at 4500+rpm.  Make sure your AAA is up to date.

[Skunky]

Hello im lookinh for advice i have 92 chevy 3500 dually with 2 barrel 454. Im having half throttle issiez boggs out half throt of full board before issue i had a return line blow off on tranny oil everyweear fixed issue then coyple weeks later started to have these half tgrottle issues after it had backfired early in morning ive replacr alot of sensors rinning out of options


Sent from my LG-LS777 using Tapatalk

Burn the bitch and get a BMW  :yow

[gag1025]

I ended up removing the plugs for a couple of days. Then I cleaned the plugs in my plug blaster, and screwed the plugs back in. I also reseated the 13 pin fuel injection control unit even though I did not feel like it had anything to do with the problem. I also squirted some oil in each cylinder just to be safe. Fortunately it started right up. and in the process it smoked up the neighborhood. Not sure which procedure solved the problem. Perhaps one or all of them. The bottom line is it now runs.

[alexg]

Probably removing the plugs to allow any fuel to dry was one important element, and dry plugs, and charged battery. :musicboohoo: